module teapo.app.files { 

  /**

   * Convert string path into an array of path parts,

   * processing '..' as necessary.

   */

  export function normalizePath(path: string): string[] {

    if (!path) return [];

    var pathMid = stripOuterSlashes(path);

    var split = pathMid.split('/');

    var result: string[] = [];

    for (var i = 0; i < split.length; i++) {

      if (split[i] === '..') {

        if (result.length)

          result.length--;

        continue;

      }

      else if (split[i] === '.' || split[i] === '') {

        continue;

      }

      else {

        result.push(split[i]);

      }

    }

    return result;

  }

  function stripOuterSlashes(path: string) {

    var start = 0;

    while (path.charAt(start) === '/')

      start++;

    var end = Math.max(start, path.length - 1);

    while (end > start && path.charAt(end) === '/')

      end--;

    var pathMid = start === 0 && end === path.length - 1 ? path : path.slice(start, end + 1);

    return pathMid;

  }

}